In the treatment of heart diseases it is important to determine the overall effectiveness of the heart as a pump, and also the ability of the blood vessels to carry blood to other organs. It is well known that blood vessels may be become clogged or the walls lined with atheromatous plaque causing a restriction of the blood flow. If the blood flow within a vessel is significantly restricted, organs that depend on that flow may be damaged, and if the flow is stopped death may occur. Consequently, the measure of the blood flow within a blood vessel has been used as an indicator of the condition of the blood vessel and the pumping action of the heart. By monitoring the blood flow of a patient, the early detection of a heart condition is possible, and preventive measures may be taken to address any problems. If the blood vessel is seriously clogged, angioplasty or a by-pass operation may be performed that utilizes a graft to circumvent the damaged vessel.
In overseeing the condition of a patient's blood vessel, a number of blood flow measurements may be needed, over time, to effectively monitor the patient's condition. One known method of monitoring the flow in a blood vessel involves the percutaneous application of an instrument to measure the flow. Such methods are termed "invasive" in that the body must be pierced in order to measure the flow. Clearly, invasive techniques to measure blood flow have a disadvantage in that the measurement must be taken under controlled conditions. For example, it becomes very difficult if not practically impossible to monitor blood flow during periods of increased exercise.
Considering the above, it is apparent that a device that non-invasively measures the flow of blood in a blood vessel is desirous. Such a device would be implanted subcutaneously within the vessel as a stent, and activated by an external power source to measure the flow of blood in the vessel. It would be advantageous for the device to communicate with an external blood flow monitor to display the blood flow information. Since the measuring process is completely non-invasive, this technique permits monitoring of the blood flow under more extreme conditions for the patient, such as undergoing strenuous exercise or after given an appropriate drug.
It is thus an object of the invention to provide a stent that may be implanted in or around a blood vessel to measure in a non-invasive manner blood flow through the vessel.
It is a further object of the invention to provide a stent that may be implanted in or around a blood vessel to measure blood flow in a non-invasive manner that is powered transcutaneously.
It is a further object of the invention to provide a stent that may be implanted around a blood vessel to measure blood flow in a non-invasive manner that includes a digital microchip having a memory to store patient data.